1. The Technical Field
The present invention relates generally to systems and methods for providing haptic feedback in connection with, for example, rotary knobs, sliders, and the like.
2. The Related Art
It is known to incorporate a mechanical detent mechanism with a rotary knob to provide the user with tactile feedback regarding the movement and relative position of the knob. Such detent mechanisms typically establish one or more predetermined detent positions toward which the mechanism biases the knob. Typically, some amount of play or slop is associated with each detent such that the biasing force does not precisely center the knob within the detent. Such systems are commonly found in radio and appliance controls.
In order to turn the knob from one detent to the next, a user must apply a force overcoming the biasing force. The applied force necessary to overcome the biasing force typically rises linearly toward a peak and then falls linearly toward a minimum as the knob is turned away from a first detent and toward a second detent. The applied force may remain near such minimum as the knob is further rotated through a region of play. As the user continues to turn the knob away from the second detent and toward a third detent, the user must again apply a force overcoming the biasing force, which applied force may have the same or similar characteristics as set forth above. This phenomenon is illustrated in FIG. 1.
The tactile feedback provided by such prior art systems is less than ideal in at least some circumstances, particularly with respect to the inherent play and/or the discontinuous applied force characteristics illustrated in FIG. I and discussed above. Among other things, these factors can render a control knob difficult to operate precisely and can give such a knob a “cheap” feel.